It will be appreciated that the invention has a wide general use to handling film-like materials, but for the purpose of description it will be discussed as applied to a copper clad laminate.
A copper clad laminate is the basic material used to produce printed circuit boards containing electrical components, such as capacitors, resistors, transistors, or more recently, micro-electronic chips. In the curing or laminating process, a glass sheets pack, containing a resin, is bonded in between two copper sheets to form what is commonly called a rigid board, or several copper sheets may alternate with a glass sheet to form what is called a multi-layer circuit board. As is well known, the glass sheet acts as an insulator between the copper areas where the electrical conduction is to occur. To provide for the electrical conduction, some of the copper on the cured laminate unit to which the components are mounted is removed by an etching process leaving only a copper path which then is used to interconnect the various components to produce an electrical circuit.
In preparation for forming uncured copper clad laminates in a press line, the copper sheets and the packs of glass are conveyed to a material build-up area and placed onto a carrier tray in this area which area consists of an arrangement of material stations for positioning the materials for the pick-up or stacking process and heads for picking-up and depositing the materials in the build-up station. In the picking-up and depositing of the copper sheet, an inherent problem exists in that since the copper sheet is relatively thin, wrinkling of the copper and/or air entrapment between the copper and glass sheets can effect the bonding of these materials, whereby an ineffective or inefficient path for the conduction of electrical energy through the circuit is created. In order to attempt to eliminate the wrinkling and to assure the copper is laid down smoothly onto the build-up station in the build-up area, presently the operator has to use a device, such as a rod, to manually "smooth out" the copper sheet, which are important factors in its production rate. Such known procedure has proven to be expensive, timely, and unreliable. Also, in the prior arrangement, the copper sheet let-off units were arranged in line and at opposite ends of the build-up station, which created an inherent delay in the operation of the polished plate and glass pick-up heads, and the inability to properly and quickly service and maintain the let-off units.
It is therefore, an object of the present invention to provide a material build-up arrangement which will pick-up and deposit a copper sheet in the build-up area with little or no wrinkles, and thus, a minimum amount of or no air entrapment between the copper sheets and the uncured stacked sheets of material.
It is still further object of the present invention to reduce the manpower and cost presently involved whereby an accurate placement and an automatic "smoothing out" of the copper sheet onto the build-up station occur.
A still further object of the present invention is to improve the overall production performance of the sequential and interrelated operation of the various stations with reference to the build-up station.
It is still a further object of the present invention to provide an arrangement for forming at least one uncured laminate unit, consisting of several sheets of different material in a build-up area of a laminating press line comprising a build-up station for receiving said several sheets, at least two material pick-up stations, each located on opposite transverse sides and adjacent to said build-up station, each material pick-up station comprising means for supporting at least a coil of said material and for dispensing said material from said coil, conveying means located adjacent said supporting and dispensing means for picking up the leading end of said coiled material, and constructed and arranged to carry said material along said material pick-up station a distance to form an as yet unsheared desired length sheet of said material, and means located between said conveying means and said supporting and dispensing means for shearing said sheet of material; said conveying means including a means for transporting sheets selectively from said material pick-up stations to said build-up station for depositing therein.
A further object of the present invention is to provide an apparatus for picking up a copper sheet from a copper sheet pick-up station, transporting it, and depositing it into a build-up station to form at least an uncured laminate unit in a build-up area of a laminating press line, each unit consisting of a metal plate, a pack of glass sheets, and at least one copper sheet comprising a frame constructed and arranged to travel at least above said copper pick-up and said build-up stations, comprising a rectangular head mounted on said frame and having a length and a width approximately equal to that of said laminate unit and having a surface positionable adjacent to said copper sheet, chamber means in said head for receiving and delivering negative air pressure against said sheet for a copper pick-up mode and positive air pressure against said sheet for a copper sheet depositing mode, and means for delivering said negative and positive pressures to said head.
And still a further object of the present invention is to provide a method for stacking uncured copper clad laminate units in a build-up area of a laminating press line, each unit consisting of a metal plate, a glass sheet, and at least one copper sheet, and wherein a copper sheet head is used to pick up, transport, and deposit a copper sheet into a build-up station, the steps comprising uncoiling a predetermined length of copper sheet from a copper let-off unit into a copper sheet pick-up station where said copper sheet head is positionable adjacent to said copper sheet and above said copper sheet station, supplying negative air pressure into said head so that said copper sheet is picked-up by said head in a manner that the center line of said head corresponds to that of said copoer sheet, motivating said copper sheet transversely to position said head directly above said build-up station, and supplying positive air pressure into said head so that said copper sheet is deposited onto said build-up station in a manner that the center line of said copper sheet corresponds to that of said stacked laminate units.